The present invention provides an interlocking locking thrust washer assembly that functions as a single component. It's a two piece design constructed from separate upper and lower injection molded rings that interlock together. As such, the present invention provides a functional design that is also easy to manufacture.
A thrust washer is typically placed between two moving parts. Thrust washers prevent longitudinal movement and provide a bearing surface for the thrust surfaces of the part. Thrust washers are used as a bearing surface for rotary applications. They are usually made of steel, bronze, plastic, or other material with low friction coefficients. Thrust washers, sometimes called rotary thrust washers, are washers designed to prevent movement along the axis of a shaft. Thrust bearings support an axial load on a shaft. A thrust bearing can be a plate at the end of a shaft, or a device against which a collar on the shaft presses.
Thrust washers can be found in almost every appliance, machine, transportation conveyance, power tool and recreational device that has moving parts, axles, bolts, pins, bearings, and rotating components. In their simplest form, thrust washers are long-wearing flat bearings in the shape of a washer that transmit and resolve axial forces in rotating mechanisms to keep components aligned along a shaft. Thrust washers are an economical alternative to rolling thrust bearings whenever forces velocities are moderate.
Precision-engineered thrust washers are used in high-wear applications such as transmissions, power take-offs, pumps, axle assemblies, motors, and winches. Thrust washer kits contain thrust washers of varying thicknesses for correct installation during component assembly. Standard thrust washers are made for products such as automotive engines.
There is shown in FIG. 1A a top plan view of an example of a Prior Art thrust washer design. FIG. 1B shows a side view of the same. Manufacturers of specialty thrust washers typically receive specifications from their prospective customers for a new application. As such a thrust washer's geometry, that is, its part thickness, inner and outer diameters and ultimately its volume, typically emanate from specifications necessitated by the customer's application. Since the required part geometry can vary with the application, there are times when the required part size and geometry are such that the part volume is too large for an injection molding machines shot capacity. The factors for determining the proper parameters for injection molding are well documented in numerous books, one of which is entitled “Injection Molding Handbook” By Tim A. Osswald, Lih-Sheng Turng, Paul J. Gramann.
Here, the Prior Art thrust washer has an inner diameter of roughly 14 inches and an outer diameter of roughly 18.5 inches. It has a maximum thickness of roughly (0.9) inches and a minimum thickness of roughly (0.6) inches. As such, this part has an internal part volume of roughly 70 cubic inches. In this application, the geometric parameters with respect to its volume are too great for an injection molding machines shot capacity. Consequently, the part can not be made and most likely the business opportunity will be lost.
An example of the inventive thrust washer design of the present invention is illustrated in FIGS. 2A-2B. Here, the thrust washer provides component 1 and component 2 with their respective volumes. The volume of each component 1, 2 is roughly half of the prior art thrust washers total volume. This allows the two components 1, 2 to be injection molded without exceeding the machines shot capacity. The present invention meets the design requirements of the customer without exceeding the molding machines shot capacity by splitting the single ring design into two rings thus providing a functional design that is easy to manufacture.